SEA-FISHERIES LABORATORY. 289 



by comparable nets at localities up to ten miles apart; 

 but on the other hand even with these same groups there 

 may, on other dates, be very diverse hauls indicating an 

 uneven distribution. 



13. Some species, and some groups of neritic larvae 

 markedly congregate in shoals, and this also adds to the 

 unevenness of the distribution. 



14. The horizontal distribution of the plankton is 

 consequently liable to be very variable and irregular, and 

 although its characteristic constitution at different times 

 of the year may be described, it is very doubtful whether 

 any numerical estimates can be framed which will be 

 applicable to wide areas. 



15. It is clear that samples taken quarterly, 

 monthly or even fortnightly are quite inadequate to 

 convey a correct idea of the constitution and changes of 

 the plankton of a sea-area in any detail; and, conse- 

 quently, conclusions ought not to be drawn from such 

 insufficient observations. 



16. Our samples, taken weekly throughout the year, 

 and almost daily during the three most critical months, 

 give by no means too much information, but will probably 

 suffice to enable us to make that detailed comparison 

 between adjacent localities and dates which we hope to 

 publish in the next Report with a view of determining 

 the representative value of such periodic samples. 



